The World's 18 Strangest Airports: Gallery

Engineers tasked with building an airport are faced with countless challenges: The ideal location needs ample space, endless flat ground, favorable winds and great visibility. But spots in the real world are rarely ideal, and engineers are forced to work with what they have, making sure that the end product is the safest possible structure for pilots. A survey of airports around the world turns up a mixed bag, ranging from dangerous and rugged landing strips to mega-size facilities that operate like small cities. Here, PM explores the world's most remarkable airports and why they stand out.

1. Kansai International Airport

1. Kansai International Airport

Osaka, Japan

Background: Land is a scarce resource in Japan, so engineers headed roughly 3 miles offshore into Osaka Bay to build this colossal structure. Work on the manmade island started in 1987, and by 1994 jumbo jets were touching down. Travelers can get from the airport to the main island of Honshu via car, railroad or even a high-speed ferry.

Why It's Unique:Kansai's artificial island is 2.5 miles long and 1.6 miles wide—so large that it's visible from space. Earthquakes, dangerous cyclones, an unstable seabed, and sabotage attempts from protestors are just some of the variables engineers were forced to account for. As impressive as the airport is, Stewart Schreckengast, a professor of aviation technology at Purdue University and a former aviation consultant with MITRE, cautions that climate change and rising sea levels pose a very real threat to the airport's existence. "When this was built, [engineers] probably didn't account for global warming," he says. "In 50 years or so, this might be underwater."

2. Gibraltar Airport

2. Gibraltar Airport

Gibraltar

Background: Between Morocco and Spain sits the tiny British territory of Gibraltar. Construction of the airport dates back to World War II, and it continues to serve as a base for the United Kingdom's Royal Air Force, though commercial flights land on a daily basis.

Why It's Unique: Winston Churchill Avenue, Gibraltar's busiest road, cuts directly across the runway. Railroad-style crossing gates hold cars back every time a plane lands or departs. "There's essentially a mountain on one side of the island and a town on the other," Schreckengast says. "The runway goes from side to side on the island because it's the only flat space there, so it's the best they can do. It's a fairly safe operation as far as keeping people away," he says, "It just happens to be the best place to land, so sometimes it's a road and sometimes it's a runway."